Abstract: Considering the uniqueness of wetting systems consisting of three components, namely, the surface, liquid and liquid/solid interface, it is desirable to construct interatomic potentials following a consistent policy. To investigate the physical meaning of the behavior in terms of the interatomic potentials, the wetting systems are modeled by simple two-body interatomic potentials derived using ab initio molecular orbital calculations for hypothetical clusters representing the above three components. For In and Sn liquid atoms, spreading occurs on a Cu (111) surface, while in contrast, liquid atoms penetrate the substrate and form a surface alloy in the case of a Pd (111) surface.

Abstract: Reverse Monte Carlo (RMC) modeling, based on diffraction data, was applied to various
kinds of amorphous materials to visualizing the three-dimensional atomic arrangement and to
elucidate topological characteristics. For an as-grown amorphous carbon nanocoil, it could be
clarified that graphene sheets are winding and the regular ABAB… stacking is lost and the
configuration gradually changes to the hexagonal network with great regularity through heat
treatment. Voronoi analysis of the RMC model could characterize the atomic configurations for
NiZr2 and CuZr2 metallic glasses. The Zr environments are very similar in the two systems, but there
are marked differences between the polyhedra around Ni and Cu atoms. The polyhedra around Ni
atoms are dominated by prismatic-like polyhedra. In contrast, icosahedron-like polyhedra are
preferred for Cu.

Abstract: This study used molecular dynamics simulations with an embedded-atom method (EAM) potential to investigate the effect of surface roughness on the surface activated bonding (SAB) of aluminium thin films. The simulations started with the bonding process and followed by the tensile test for estimating bonding strength. By averaging the atomic stresses over the entire system, the stress-time curves for the bonded films under a tensile condition were predicted. Moreover, the evolution of the crystal structure in the local atomic order was examined by the common neighbour analysis. The simulated results show that the decrease in the surface roughness of thin film improves the bonding strength. The observed recrystallization processes inside the bonded thin films also reveal that the plastic deformation of the aluminium surface due to atomic attracting force compensates surface roughness.

Abstract: Molecular dynamics simulations were carried out to investigate the plastic deformation mechanism of fcc crystalline materials using the conventional Lennard-Jones potential. An fcc structure with square cross-section was prepared, and a tensile load was applied in the longitudinal direction. A weak potential was assigned to a specific (111) plane to induce a slip on the specified plane. Accordingly, a slip was initiated in the weak plane following an elastic deformation. The step-by-step motion of the atoms on the slip plane was studied, and a detailed trajectory is presented. The slip then expanded to other planes, and plastic deformation progressed in the whole model. The weak plane was also set as (110) or (100) plane, where different deformation modes were observed: not only slip but also gradual distortion or brittle fracture occurred.

Abstract: Using the method of molecular dynamics, FCC Ni nanowires containing hydrogen atoms in octahedral and tetrahedral pores are investigated in the course of high-speed uniaxial tensile loading along the direction <001>. The feature of structural transformations in Ni nanowires containing hydrogen is appearance on the stage of plastic deformation globular (spherical) formations consisting of hydrogen atoms